Case 12

A 68-Year-Old Male With Weakness and Fatigue

Rachel Ramirez, Daniel Martinez

A 68-year-old male is brought by his wife for worsening weakness and malaise for the past few weeks. He states that he began to feel weak, fatigued, and lightheaded with associated muscle cramps. His wife notes he has been slightly less attentive over the past 10 days, especially when extended family members were visiting. He denies any sick contacts or recent travel.

What are some things to think about when someone complains of weakness and malaise?

Generalized weakness and malaise are very common complaints in the primary care setting, and, unfortunately, the differential diagnosis for these symptoms is very broad. A “shotgun” approach by testing everything is not medically appropriate, and, instead, a thorough history, physical exam, and placing the patient’s symptoms in clinical context are of utmost importance in proceeding with an evaluation. However, you should keep the broad differential diagnosis in the back of your mind while proceeding with the history and physical so as to make sure you do not miss a significant pathology. The following Table 12.1 lists a comprehensive list of the causes of weakness and malaise.

The patient has a past medical history of hypertension and dyslipidemia, and he takes lisinopril, atorvastatin, and aspirin. He has never been screened for any sort of cancer because he would “rather not know.” He denies any drug allergies and does not take any herbal supplements or vitamins. His past surgical history includes an appendectomy in 1965. He is a retired computer engineer who has been married for 40 years. He drinks “two fingers” of scotch on Friday nights. He has a 30-pack-year smoking history with a quit date 15 years ago. He is a Vietnam War veteran and received a blood transfusion due to a combat-related injury in 1971. He has three adult children, three grandchildren, and two dogs. His hobbies include golfing, sailing, and coin collecting. On review of systems, he reports a slight cough that he attributes to the change of seasons and a recent low-grade temperature. His wife notes an approximate 15-pound weight loss. When this is commented upon, he states that this is probably because he stopped eating ice cream for dessert a few weeks ago.

TABLE 12.1

Causes of Fatigue

System Involved	Specific Conditions
Endocrine	Disorders of the thyroid, adrenal, or pancreatic endocrine glands. In this case, you would look for weight gain and constipation (hypothyroidism); weight loss, diarrhea, palpitations, and insomnia (hyperthyroidism); weight loss despite polyphagia, polydipsia, and polyuria (new-onset type 2 diabetes); or weight loss, anorexia, skin color changes, polydipsia, and salt cravings (adrenal insufficiency).
Neurologic	Disorders of the nerves and muscles can cause weakness such as myositis (autoimmune), neuromuscular blockade (Eaton-Lambert, myasthenia gravis), and demyelinating disorders (Guillain-Barré syndrome, multiple sclerosis). Normal pressure hydrocephalus can cause mental status changes, gait instability, and urinary incontinence. Stroke (ischemic) is usually associated with focal complaints (“my face is numb on one side”).
Electrolyte disturbances	These include hyponatremia, hypokalemia, and hypercalcemia. Asking about bone pain, muscle cramps, or inability to stand helps rule in or out some of these problems. Progressive renal failure with elevation of the blood urea nitrogen causes anorexia, fatigue, nausea, and muscle cramps.
Cardiac	Any cardiac disease (structural or electrical) that reduces cardiac output will cause weakness and malaise. Congestive heart failure (CHF) and atrial or ventricular arrhythmias are examples, so you should inquire about palpitations, chest pain, shortness of breath, and lower extremity edema. It is also important to ask about prior coronary artery disease (CAD). Valvular heart disease, like aortic stenosis or aortic insufficiency, mitral valve stenosis, or prolapse, reduces cardiac output and shifts the cardiac pressures in the wrong direction (backward toward the lungs), so shortness of breath may be an important clue.
Infectious	Chronic or subacute infections can contribute to malaise and weakness. Tuberculosis is a chronically progressive infection that also has cough, weight loss, and night sweats as components. Subacute bacterial endocarditis (SBE) often causes a host of nonspecific complaints, but fevers and night sweats are common. Chronic viral infections such as hepatitis B or C can cause fatigue. Historical data acquired should include past blood transfusions, past intravenous drug use, sexual history, and tattoo acquisition. Infectious mononucleosis (IM) is notorious for causing fatigue. Antecedent pharyngitis and swollen lymph nodes are important features of IM. Human immunodeficiency virus (HIV) infection, in the acute phase, can cause fatigue but is often associated with fever, pharyngitis, and adenopathy.
Hematologic and malignant conditions	Anemia of any cause can manifest as fatigue. Careful history about blood loss via stool or urine, as well as iron and other nutrient intake, is important. Hematologic malignancies like leukemia and lymphoma also cause fatigue. Associated fever, night sweats, bruising, or adenopathy are clues.
Gastrointestinal disorders	Cirrhosis and inflammatory bowel disease can cause fatigue. Make sure to look for abdominal pain, blood in the stool, and weight loss.

What pathologies should you be considering based on this history?

There are many classic “buzz words” that can be observed when taking a history that should lead you to consider certain pathologies. The more you take a detailed history, the more they and their associated pathologies will become second nature. In this case, Table 12.2 lists some of these buzz words and the associated pathologic consideration.

The patient’s blood pressure is 128/75 mm Hg, pulse rate is 82/min, respiration rate is 12/min, body mass index is 18. He appears unwell and slightly undernourished, but he is in no acute distress. He is awake and oriented to person, place, time, and purpose. His cranial nerves are intact, and he has pink conjunctiva with moist mucus membranes. There is no jugular venous distension, lymphadenopathy, or bruits in the neck. His heart has a regular rate and rhythm without extra heart sounds, murmurs, clicks, or rubs. He does not have a barrel chest, and his lungs sounds are clear to auscultation bilaterally. His abdomen is soft with no evidence of hepatosplenomegaly or masses. On rectal exam, he has soft brown stool, a normal sized and smooth prostate, with no abnormal masses. His skin has no tenting, bruising, or rashes. His joints have full range of motion and are without erythema or swelling. He is able to get out of a chair without use of his arm, and he has no motor, sensory, or coordination deficits. He has no peripheral edema. He has clubbing of his nails, but no dilation of the capillary beds.

TABLE 12.2

Key Buzz Words in This Case and How They May Contribute to the Clinical Assessment

Buzz Words	Pathologic Consideration
“weeks”	Indicates a relatively new-onset, but not immediate, constellation of symptoms.
“less attentive”	Translate as “change in mental status.” This indicates the issue has begun to affect his mental acuity.
“muscle cramps”	His are diffuse and not limited to one muscle group and can suggest a metabolic derangement.
“hypertension” and “dyslipidemia”	Increases his risk for CAD and cerebral vascular disease.
“lisinopril”	Can cause hyperkalemia, acute kidney injury, and a dry cough.
“atorvastatin”	Most statins can cause muscle cramps and weakness.
“aspirin”	Can cause gastrointestinal ulcers and bleeding. This can lead to anemia and fatigue.
“cough”	Consider pulmonary process like tumor, tuberculosis, chronic obstructive lung disease, interstitial lung disease, or a medication side effect.
“low-grade temperatures” and “weight loss”	Consider malignancy, infection, and autoimmune disorders.

How does this change your differential diagnosis?

His normal vital signs point away from an infectious process, but this is not completely excluded yet. He appears undernourished and given his age and weight loss history, malignancy is now higher on the differential. However, the lack of diffuse lymphadenopathy and normal prostate exam are reassuring at least from a diffusely metastatic disease or prostate cancer standpoint. The pink conjunctiva make anemia unlikely. His moist mucus membranes and lack of skin tenting make dehydration unlikely. His normal cardiac and pulmonary exam and lack of jugular venous distension (JVD) or peripheral edema make heart failure, chronic obstructive pulmonary disease, and interstitial lung disease unlikely. His normal musculoskeletal exam, lack of skin rash, friction rub, or decreased breath sounds (pleural effusion) make a rheumatologic disease less likely. His good muscle strength and normal sensation and coordination make a neurologic disease very unlikely. And lastly, his nail clubbing in light of his history of smoking and weight loss makes lung cancer a distinct possibility.

What labs should you order next?

At this point, his history and physical exam point to some sort of malignancy. Given his specific clinical scenario, he is at greatest risk for lung or colon cancer. But since he has no lymphadenopathy, unlikely significantly anemic, and he is not severely cachectic, it is unlikely that just the malignancy itself is very advanced to the point of causing his symptom of fatigue and malaise.

At this point, lung cancer is known to have many metabolic derangements associated with it, so getting a basic metabolic panel is warranted. Since colon cancer is reasonably on the differential, it might be metastatic to the liver, so ordering a liver profile is appropriate as well (see Table 12.3).

You review the labs and appreciate that his sodium level is very low which can explain his chief complaints. You suspected a metabolic derangement before the labs, and this confirms your diagnosis. You tell the patient that his fatigue and malaise are likely due to a low sodium concentration in his body and would like to admit him to the hospital for further work-up and treatment.